The present invention relates to speed regulation of a music box, and more particularly, to a flying block assembly for speed regulation which provides for easy adjustment by integrally supporting an inertia frame on a flying block assembly.
In the prior art, the speed regulating flying block of a music box is movably mounted on a speed regulating shaft on an unthreaded portion of the shaft. By applying hand pressure, the relative position of the flying block assembly to a damping friction disk, i.e., the distance between each of them, can be changed, so that the speed of playing music by the music box will be varied. Since the damping friction disk has a tapered surface opening downwardly and is located above the speed regulating flying block assembly, when the distance between the flying block and the damping friction disk is decreased frictional contact with arise more quickly between the flying blocks of the fling block assembly and the damping friction disk by the action of centrifugal force. Resistance to the energy release of a spiral power spring of the music box will be caused in this way, and the spring will meet such resistance more quickly. The time to play back a tune will thereby be extended and slower playback will result. On the contrary, when the speed regulating flying block assembly is adjusted to be relatively further from the damping friction disk, the frequency of frictional contact between the flying blocks and the inner tapered surfaced of the damping friction disk will be relatively less. The time for playing a tune from the beginning to the end will thereby be shortened, so the playback speed of a tune will be faster.
In the prior art of Chinese patent CN 21747671 Y (see FIGS. 5 and 6), an inertia frame fitted on the speed regulating shaft is not movable, which restricts the moving range of the speed regulating flying block in the axial direction of the speed regulating shaft. The speed regulating shaft of the music box in this conventional arrangement includes an upper section and a lower section, and is threaded on the lower section end and unthreaded on the upper section. A significant portion of the unthreaded portion is occupied by the inertia frame, and since the unthreaded portion has a limited length in the axial direction, an insufficient range of adjusting movement is available for the speed regulating flying block in the axial direction.